﻿Re-Entry of Soyuz Rocket Stage observed from Hungary﻿

November 26, 2014

A number of observers in Hungary spotted the re-entry of the Block I upper stage of the Soyuz FG rocket that launched the Soyuz TMA-15M spacecraft carrying three new crew members to the International Space Station. Witnesses from north-western to south-eastern Hungary reported seeing a fireball moving across the sky at around 4:40 a.m. local time on Wednesday.

Meteor cameras deployed across the country detected the event at 3:39 UTC and data from the observatories indicates that the object was moving at 7.3 +/-0.5 Kilometers per second, confirming that it was an object re-entering from orbit.

A camera deployed near the town of Szombathely in north-western Hungary registered the event at 3:38:50 UTC while the HUBEC Camera 65km south east from HUGOT shows the event taking place between 3:39:18 and 3:39:30 UTC.

The HUHOD camera located in south-eastern Hungary, 300 Kilometers from the other observatories, shows the event at 3:39:24 UTC.

HUBEC

Image: videometeor.hu - HUBEC

HUHOD

Image: videometeor.hu - HUHOD

HUGOT

Image: videometeor.hu - HUGOT

Witnesses described the event as a long-lasting fireball moving at a relatively low speed and showing a growing debris tail as it moved across the sky. Fragmentation is typical for re-entering spacecraft.

The identity of the re-entering object is confirmed by the U.S. Joint Operations Center that shows the SL-4 Rocket Body of the Soyuz TMA-15M launch to have re-entered at 3:39 UTC +/-1 Minute over 17°E 47°N – an accuracy achieved by using space-based assets to track the re-entry signature of spacecraft. Time and location are a perfect match for the observations.

Launching from the Baikonur Cosmodrome at 21:01 UTC on Sunday, the third stage of the Soyuz ended up in an orbit just 200 Kilometers in altitude from where the Soyuz TMA-15M spacecraft started its rendezvous with the Space Station, boosting its orbit to over 400 Kilometers to conduct a four-orbit rendezvous, delivering the Expedition 42/43 crew to ISS.

The orbit of the Block I third stage of the Soyuz was extremely short lived due to its low altitude and the increased drag in the uppermost layers of Earth’s atmosphere which slows the vehicle down and causes it to drop toward the dense atmosphere.

Even at altitudes of more than 200 Kilometers, the thin atmosphere consists of atoms and molecules that collide with the spacecraft and slow it down as a result.

The exact speed of the orbital decay depends on the current state of the atmosphere which is known to expand and contract as a result of solar activity. Once hitting the dense atmosphere, the vehicle starts feeling the effects of re-entry. The precise altitude of the start of re-entry depends on atmospheric conditions.

Generally, destructive re-entry starts at an altitude of 120 to 100 Kilometers as the spacecraft is rapidly slowed down and dips into the dense layers of the atmosphere.

As the spacecraft re-enters, heat starts building on the vehicle and aerodynamic forces occurring at the high entry velocity cause the satellite to break up. Beak-up and disintegration of the vehicle usually occurs at around 80 Kilometers. Most components of the disintegrating spacecraft burn up harmlessly in the atmosphere and never reach the ground, especially for rocket bodies that consist for a large part of thin metal that forms the propellant tanks. However, dense components such as pressurant tanks and engine components can survive re-entry and reach the ground.

The third stage of the Soyuz is 2.66 meters in diameter and 6.74 meters in length with an empty mass of 2,355 Kilograms featuring a single RD-0110 engine with four chambers. Dense components of satellites usually impact 800 to 1,300 Kilometers downrange from the Orbital Decay Point. Their journey back to Earth is strongly influenced by atmospheric properties like crosswinds that play a major role during atmospheric descent.

Shindaisat

Re-Entry Prediction: November 24, 2014 - 04:45 UTC +/-120 MinuteRe-Entry Zone: UnknownShindaiSat, also known as Ginrei, is a 35-Kilogram satellite developed at Shinshu University to demonstrate LEDs (Light Emitting Diodes) as an optical communications link over large distances of more than 400 Kilometers. >>>Detailed Technical Overview

The SkyCube satellite is a project of Southern Stars Group LLC. Crowd-funding was used for the mission and investors get a chance to transmit a message from space or take pictures of locations of their selection. SkyCube is a 2-Kilogram one-unit satellite that features deployable solar panels, four cameras and communication antennas that are used to receive messages from Earth that are then transmitted at pre-determined times. Investors are able to send 120-character messages or request images of chosen locations using the satellite's low-resolution cameras. The satellites uses the 915MHz band for imagery downlink using a 57.6kbps modem. Towards the end of its mission, the satellite will deploy a 3-meter inflatable balloon to speed-up re-entry and make it visible to observers on Earth. The balloon consists of low-density polyethylene coated with highly reflective titanium dioxide to make it visible. The balloon is inflated using a 4-gram carbon dioxide cartridge.

Re-Entry Zone

Image: Orbitron

Background

Kosmos 1400 was a Tselina-D satellite that was used to track radio emissions around the globe – tracking their location, type, mode of operation and activity to provide intelligence and important information for tactical military operations.

Space-based surveillance can provide situational awareness of activity in foreign territory, and early warning capabilities that may be unavailable by other methods.

The Tselina electronic intelligence satellite program was initiated in 1964 with the development of two types of spacecraft – Tselina-O that were smaller satellites to make low-sensitivity measurements to provide an overview of radio activity over a large ground area, and the high-sensitivity Tselina-D satellites for precise measurements of locations of interest.

The Tselina program saw its first launches in the mid-1960s when test payloads were launched on two experimental satellites (both failed) before the first Tselina-O spacecraft launched in 1967. The Tselina-O satellites had a mass of around 450 Kilograms and operated in orbits at around 530 Kilometers at an inclination of 74 degrees. Tselina-O saw more than 40 launches until 1982.

The first Tselina-D satellite was launched in 1970 and was followed by nearly 70 satellites launched until 1994.

Image: Yuzhnoye

Tselina-R - Similar to Tselina-D

The Tselina-D satellites had a launch mass of about 1,800 Kilograms and had an expected operational life of six months. The satellites operated in orbits around 550 Kilometers at different inclinations around 80 degrees. Tselina-D satellites built a constellation with satellites in several planes spaced by 30° in the early phase of the program and 60° later in the program. After the retirement of Tselina-O in 1984, Tselina-D took over general ELINT surveillance operations.

Four improved Tselina satellites known as Tselina-R were launched between 1986 and 1993.The early Tselina constellation had the drawback that it only provided recorded data that was stored onboard the spacecraft until they could downlink acquired data to Russian ground stations. The improved Tselina-2 satellite generation was capable of downlinking data in real time via Geosynchronous data relay satellites. These satellites have a launch mass of 3,300 Kilograms and an expected lifespan of more than one year. The first Tselina-2 launched in 1984 and was followed by 22 more launches until 2007 using Proton-K and Zenit-2 rockets. Tselina-2 and –D complemented each other while both were in operation as Tselina-2 operates in higher orbits at 850 Kilometers with a spacing of 40° in between planes.